Effect of the Microwave Heating on Diffusion Kinetics and Mechanical Properties of Borides in AISI 316L

A Kinetic Study of Thermochemically Borided Aisi 316l Stainless Steel

“…The highest coating thickness was reached in boriding at 1050°C for 6 h and the obtained coating thickness value was 60.9 µm. It is also seen that similar coating thicknesses were obtained in a boriding study [30] performed on AISI 316L steel with Ekabor-2 (6.2 -63.5 µm). It is reported that the coating thickness obtained in another study, in which continuous boriding was performed on AISI 316L stainless steel with Ekabor-2 at 900°C for 1 h, was approximately 13 µm [31].…”

“…Activation energy results of some boriding studies made by different boriding methods were given in Table 4. Activation energies for the formation and growth of boride layers are consistent with the literature as can be seen from Table 5 [30,31,[36][37][38][39][40][41][42][43][44][45].…”

“…Micrographs showing the boride layers of metallographically prepared sections of borided specimens at 850 °C and 1050°C for 6 h were given in Figure 1 In Figure 1a, the boron-rich transition zone cannot be seen clearly because the boriding temperature is not very high. It is pointed out in many studies that boride layer formed in the tooth-like form in the pure iron and plain carbon steels [28], and formed in the form of plain-like -not in the form of toothlike-in the alloyed steels depending on the alloying elements [29][30]. It is seen that the coating thickness obtained for boriding at 850°C for 2 h is 9.8 µm.…”

Kinetic Modelling of Powder-Pack Boronized 4Cr5MoSiV1 Steel by Two Distinct Approaches

“…Table 3 groups the different values of boron activation energies obtained on some alloyed borided steels [22,27,[33][34][35][36][37][38][39][40][41][42] and compares them to the present results from the bilayer model. It is seen from Table 3 that the values of the activation energies were affected by several factors.…”

“…As an illustrative example, Rafidah et al [43] machined different geometrical shapes of grooves on the cubic samples of treated mild steel. These samples were pack boronized at 1123, 1173, and 1223 K for 2, 4, and 6 h. In case of powder-pack boronized high-alloy steels [22,38,39,41], the obtained activation energies were high compared to the plasma-paste boriding [33,34]. For the powder-pack boriding, a plausible explanation could be the change in the values of the boron activity in the contact area between the powder mixture and the steel surface during the process, which could have drastically lowered the diffusion rate of boron atoms inside the substrate.…”